Pit prop



w. sYLvEsTER PIT PROP Filed Jan. l2, 1333 3 Sheets-Sheet l Nov. 6, 1934.

3 Sheets-Sheet 2 W. SYLVESTER PIT -PROP Filed Jan. l2, 1333 Nov. 6, 1934.

Patented Nov. 6, 1934 invase; Q

4PrrPRoI" Walter Sylvester,

Tunstall.. yEngland- Application January "12, 1933, lSerial No. '651;343

xIn(rrea: Britain Januaryf2`3`, 1932' 14 Claims.

This invention relates'to pit propsand. more particularly to Wedge-type pitprops which comprisealcasing mounted y.onthe endof the Vprop and .ay wedge mounted in the casing engaging the endof `the prop andthe casing or a head piece. and` arranged for driving in. to nx or .tightenthe prop after .it hasbeen set in place.

.Wedge-type pit props, while they are simple iii-construction andinpractice the easiest props to `fix, have the serious disadvantage that considerable risks have. to be .taken in removing them. Afprop of thiskind' is removed by driving out the wedge With a sledge hammer and atv the last. the release is sudden. andmay be followed by such `a sudden and heavy fall of the roof"as to endanger thesafety of the person y.removing i it.

`The object .of the inventionis an improved wedge-type. pit .prop not'having the above disadvantages.

-According to the invention, `the pit prop is .characterzedin that the casing, which locates `the Wed-ge on the.prop,is"formed with. an open front or side so that theprop may be withdrawn laterally-.from under the Wedge.

.In `the, accompanying drawings:-

Fig. `1 isa side elevation of. one example of pitprop made in accordance with'the invention.

Y1i'g..2 isa'front elevation oitheprop shown in lig. l.

Fig. 3 is a side. elevation showingtherelation oithe parts; during removal of theV prop.

Figs. 4 and 5 are side and` front elevations of a modiiied'forrnof theinvention.

vFigs. 6 and "1.' are sideand' front Aelevations of another modined form of the'invention.`

Figs 8 and 9 are side and "front elevations `of a further modified form of the invention.

` Figs. 10 and'll' .are side' and' front elevations of a modied constructionA ofcasing incorporat- `ingthe head piece.

As illustrated in Figs;`1 to 3, the girder Vprop 12 having flanges 13 is tted with anA inclined cap `14. On ,the longer flangernea-r the cap 14 are secured two lugs 15 having elongated slots 16, reinforcingpieces 11 being provided behind those .parts of the ange; To these lugs is pivoted a member constituting a combinedlocking lever and link for drawing the propi the member consisting of two locking levers 18, con- .nected` by a Ueshaped .bridge 19, and being attached' by means of apivot `bolt Y20 positioned .at the junction of 'the .levers and bridge piece "and passing through and adapted to move freely inthe slots .16 of the lugs l5v on the prop. Each. lever 18 has atits'end an inwardly directed lug '2`1` having-an arcuate face directed towards the pivot. The b'o1t,:20'" is" secured by a vpin 22-and Washer 23.

.60 On .theend .of "the prop is also` arranged-a casingli' ,having afsocketlke upper end to `reeeilve' and. locate a. ,head `piece 25. LB`eloW Vthe socketwwhich may beerectangularpr round, the casing isinshape three sides Vof a `rectangle of a.size`adaptedl to t' overthe end of the prop'. InI one .ormboth of; the `wingsV or sides `of this lower `part is (a study2`6 which byA `engagement with the ,c'aple or ilanges 13' prevents the cas'- ing `fromleavingthe Iprop. Within thisglower part of' thefcasing E.also slidably `arranged a wedge L2'lfpassi`ng through a slot 28T in the rear Wall of the casing and located by' a bolt 29 `in olie-sides,v the .end of which ,bojltv engages 'in a groove `3U ,in Vthe side ofthe Wedge. Onthe 'sides offthe lbwerpartofjthe casing areformed lugs 31. l having arcuate faces to be engaged by the arcuateaces 21' ofthe leversY 18, the ends 32gof` the faces 4of `the lugsyl. being rounded off to give a lead. 'The sides ofthe casing are also extended. andiormcd with a notch 33"adapted to engage ahub-part provided ateach lever around the pivot'bolt.`

For' withdrawing' the "prop a chain *linkf"35 is provided. on the member' 19 to which the' chain oi" Ythe. drawing. Amachine may be connected. Thisjlinl {i5/nasa lockingjpin' attached to t'by Aa; short' chain 37 the locking upin being adapted to be inserte'diin aholein one side .of thecasing `24 under' the lug121to prevent the rel'easingm'ovement ofthe lever`18. The chain 371i`s purposely made' 'short so that` the `pin re*- duirestobe Withdrawn: before theY chain ofthe drawing machine. can be attached to the' linkf35.

iThe casing may be madel'from sheet metal by .fjolding andthe sides maybe' made with a corrugation on', either side;` in which the wedge may fbe' located. and guided. by a flange along its upper edge, suitable stops being provided to retain the wedge. 'Preferably alsothe engaging faces of the e prop cap `and wedge Will be ,smooth and jof" hardened. steelt i jIn use. the `prQlfhis' quicklyrtted. Firstly/if notl already sopositioned, the casing is brought to the c'aph end of' the'A prop; and' the" levers.y moved into the position shown'V in Fig; 1) locking the cas- `ing on to' the' en'dl ofthe prop'. `The' wedgeiZ'T is then y:irait/noni', to its extreme position and the prop with its' head' piece is placed inposition, with .a lid ii' necessary,` inthe usuall manner and the prop'nn'ally secured by driving in' the wedge.

To remove the plQl); the chain ,of anytype of drawing machine is attached tothelink-, .the pin' 3.6`.beingpreviouslyv withdrawn to facilitatesuch attachment; .As apull i'sgapplied, the U -shaped bridge piece or link 191fliftsz intoA the horizontal position-'and with suchmovementit brings the' levers 21n out of engagement with the lugs 1'8. -liurther pullingv onthe-br-idge piece or link-is new@only1'icommunicated to the 4upper end of the propL itself-.".wnichbeingnolonger locked in the casing is readily drawn away from under the wedge.

In the modined form of the invention as shown in Figs. 4 and 5 the prop 38 is provided with a single lug 89 on the front flange 40 in which is pivoted on a pin 41 a locking bar 42, To the lug 39 is also pivoted a draw-link 43 on a pivot 44, one arm of the link having a hooklike extension adapted to engage the locking bar 42. The sides of the casing 46 are extended forward and shaped to provide hook-shaped lugs 47, one of which is turned upwards and the other downwards. In other respects, the parts of the prop are similar in construction to those in Figs. l to 3. Locking means to prevent accidental release of the prop may also be provided.

In use, the casing is shown in Figs. 4 and 5 locked on to the end of the prop. By connecting the draw chain to the end of the link 43 and after releasing any locking means, the rst movement caused by pulling on the chain will be to raise that end'of the link andby the engagement of the hook-like extension 45 with the locking vbar 42, the latter is caused to rotate to the position shown in dotted lines in Fig. 5, or at least, so' as to disengage from the lugs 47. The casing 46 is thus unlocked from the end of the prop and further pulling on the draw chain can act to draw the prop from under the wedge 48 and from out of the casing 46. The prop is fixed in the same manner as in fixing the prop shown in Figs. 1 to 3, by first locking the casing on to the prop and using the wedge 48 to tighten the prop in position.

As shown in Figs. 6 and 7 the prop 49 is provided with a single lug 50 on the front flange 51, in which lug is pivoted at 52 a link 53, the bifurcated ends of which are extended to provide hooks 54. A connecting link 55 is also provided on the link 53. The sides of the casing 56 are extended forward to provide two upwardly directed hooks 57 in which may be disposed a locking bar 58. In other respects the parts of' the prop are similar in construction to those in Figs. 1 to 3. Locking means to prevent accidental release of the prop may also be provided.

In use, the casing is shown in Figs. 6 and 7 in position locked on the end of the prop. By connecting the draw chain to the link 55 and after releasing any locking means the first movement caused by pulling on the chain will be to pull down the link 53 so that its hooks 54 displace the locking bar 58 from the hooks 57. The casing 56 is thus unlocked from the end of the prop and further pulling on the draw chain can act to draw the prop from under the wedge 59 kand out of the casing 56. The prop is fixed in the same manner asin xing the prop shown in Figs. 1 to 3, by rst locking the casing on to the prop and using the wedge 59 to tighten the prop in position.

As shown in the further modified example illustrated in Figs. 8 and 9, the prop 60 is provided with a casing 61 with a front 62 pivoted to the sides of the casing at 63 near its top edge. On the web of the prop are provided lugs 64 to which are pivoted S-shaped locking members 65 having operating arms 66 and the hooked ends of which are adapted to engage lugs 67 and 68l on thecasing and casing front respectively. In other respects the parts of the prop are similar in construction to those in Figs. 1 to 3.

yLocking means to prevent accidental release of the prop may also be provided.

In use, the casing is shown in Figs. 8 and 9 in position locked on the end of the prop. 'By connecting the draw chain to the arms 66 and after releasing any locking means, the first movement caused by pulling on the chain will be to rotate the Sshaped locking members 65, so that their hooked ends are disengaged from the lugs 67 and 68. The casing 61 is thus unlocked from the end of the prop, further pulling on the draw chain acting to draw the prop from under the wedge 69 and out of the casing, the front 62 swinging up on its pivot to allow of such Withdrawal of the prop. The prop is fixed in the same manner as in xing the prop shown in Figs. 1 to 3, by rst locking the casing on to the prop and using the wedge 69 to tighten the prop in position.

As shown in Figs. 10 and 11 the prop 70 is provided with a casing 71 formed of bent welded plate metal, at the top of which is provided a iixed head 72 soA that the head and casing are combined as a single unit. The casing is formed with a rearwardly inclined rear side 73 so as to give an overhang for the head. In other respects the parts of the prop are similar in construction to those shown in Figs. l to 3. Locking means to prevent accidental release or the prop may also be provided as shown in Figs. 1 to 3.

In use the casing is shown in Figs. 10 and l1 locked on to the end of the prop. During withdrawal, it has been found occasionally that the prop shown in Figs. l to 3 may have a tendency to resist withdrawal when the prop is partly drawn. t is believed that this resistance is caused by a possible tilting action of the head .'fii.

and casing, owing to the fact that the prop has become slightly tilted and the rear edge of the top of the prop forms a ulcrum on which the head has a tendency to tilt forward. For this reason the overhang above mentioned is proif,

As will be obvious, the invention is not limited to the details of the example above given, the principal features of the invention being the provision of a casing which enables the prop to be withdrawn from under the wedge.

The invention is applicable to other types of prop besides the H-section girder prop herein described.

What I claim is:-

1. A pit prop comprising a post, a casing or helmet loosely fitted on the upper end of the post and having an opening on one side large enough for the end of the post to pass through laterally, a wedge passing through the casing and over the upper end of the post with its smaller end nearer the said opening and locking means across the said opening for retaining the post within the casing.

2. A pit prop comprising a post, a casing or helmet loosely fitted on the upper end of the post and having an opening on one side large enough f within the casing, said locking means compris` ing a pivoted latch on the post and comple`` mentary locking means on the casing.

3. A pit prop comprising a post, a casing or helmet loosely tted on the Lipper end of the post and having an opening on one side large enough for the end of the post to pass through laterally, a wedge passing through the casingY and over the upper end of the post withits smaller end nearer the said opening and locking mean across the said opening for retaining the post within the casing, said locking means including a pivoted member, having an arm which lies against the post when the said member is in the locked position and which is moved away from the post to unlock said locking means. p

4. A pit prop comprising a post, a casing or helmet loosely fitted on the upper end oit the post and having an opening on one side large enough for the end of the post to pass through laterally, a wedge passing through the casing and over the upper end of the post with its smaller end nearer the said opening and locking means across the said opening for retaining the post within the casing, said locking means including a pivoted member having an arm which lies against the post when the said member is in the locked position and which is moved away from the post to unlock said locking means, said arm being shaped for engagement by a prop withdrawing means.

5. A pit prop according to claim 2 wherein the locking means comprises a U-shaped member pivoted near its extremities to the post, extensions of said extremities projecting at right "angles therefrom to extend along the sides of the casing and complementary locking formations on the said extensions and on the sides of the casing positioned so as to be engaged when the U-shaped member is lying against the post.

6. A pit prop according to claim 2 wherein the locking means comprises a U-shaped member pivoted near its extremities to the post, extensions of said extremities projecting at right angles therefrom to extend along the sides of the casing and complementary locking formations on the said extensions and on the sides of the casing positioned so as to be engaged when the U-shaped member is hanging beside the post from its pivot.

'7. A pit prop according to claim 2 wherein the locking means comprises a U-shaped member pivoted near its extremities to the post, extensions or said extremities projecting at right angles therefrom to extend along the sides of the casing, complementary locking formations on the said extensions and on the sides of the casing positioned so as to be engaged when the U-shaped member is lying against the post and a chain link on said U-shaped member to receive the hook of a prop withdrawing machine.

8. A pit prop according to claim 2 wherein the locking means comprises a U-shaped member pivoted near its extremities to the post, extensions of said extremities projecting at right angles therefrom to extend along the sides of the casing, complementary locking formations on the said extensions and on the sides of the casing positioned so as to be engaged when the U-shaped member is lying against the post, a chain link on said U-shaped member to receive the hook of a prop withdrawing machine, and a locking pin adapted to be inserted into a hole in the side of the casing below one of the said extensions to prevent accidental unlocking movement of the U-shaped member and a relatively short chain connecting said locking pin to the chain link so that when the pin is in its hole the said link is held too close to the U-shaped member for the link to receive the hook of the prop withdrawing machine.

9. A pit prop comprising a post, a casing or helmet loosely tted on the upper end of the post and having an opening on one side large enough for the end of the post to pass through laterally, a wedge passing through the casing and over the upper end of the post with its smaller end nearer the said opening and locking means across the said opening for retaining the post within the casing, the said casing or helmet having an overhang relative to the post away from the said opening.

lo. A pit prop comprising a post, al casing or helmet loosely tted on the upper end of the post and having an opening on one side large enough for the end of the post to pass through laterally, a wedge passing through the casing and over the upper `end of the post with its smaller end nearer the said opening, locking means across the said opening for retaining the post within the casing, and means for slidably attaching the casing to the post and the wedge to the casing.

11. A pit prop comprising a post, a casing or helmet loosely` fitted on the upper end of the post and having an opening on one side large enough for the end of the post to pass through laterally, a wedge passing through the casing and over the upper end of the post with its smaller end nearer the said opening, locking means across the said opening for retaining the post within the casing comprising normally fixed but removable projections on the casing entering closed-ended recesses in the post and wedge.

12. A pit prop comprising a post, a casing or helmet loosely tted on the upper end of the post and having an opening on one side large enough for the end of the post to pass through laterally, a wedge passing through the casing and over the upper end of the post with its smaller end nearer the said Opening and locking means across the said opening for retaining the post within the casing, said locking means comprising a latch bar pivoted centrally to one side of the post, hook-shaped extensions from the side of the casing, one facing upwardly and the other downwardly, with which the ends of the latch bar engage when positioned across the post and a lever pivoted beside the latch bar engaging the said latch bar to move it about its pivot from out of engagement with the said hook-shaped extensions.

13. A pit prop comprising a post, a casing or helmet loosely tted on the upper end of the post and having an opening on one side large enough for the end of the post to pass through laterally, a wedge passing through the casing and over the upper end of the post with its smaller end nearer the said opening and locking means across the said opening for retaining the post within the casing, the said casing or helmet having a loose head-piece resting on the upper side of the wedge and slidable in the upper end of the casing.

14. A pit prop according to claim 13, further characterized by connecting means between the head-piece and the casing, to hold the headpiece captive to the casing whilst allowing of the sliding movement of the head-piece.

WALTER SYLVESTER. 

